Many of us are told from a young age not to swallow toothpaste because it’s bad – and this is true, up to a point. Toothpaste contains lots of fluoride, and while this mineral strengthens enamel and protects teeth from decay, in large quantities it is poisonous.
Ingesting a large amount can lead to vomiting and weakness, explains Karen Coates, a dental health adviser from the British Dental Health Foundation. But you’d need to swallow a whole tube in one go, she says.
“If you’re somewhere where you’re unable to spit out the toothpaste, then swallowing is fine,” she adds. “In fact, you don’t need water at all. Rinsing your mouth with water is likely to wash away fluoride, and it’s best to keep it around the teeth.”
Wetting the toothbrush isn’t necessary either – and may be a bad idea. “It can alter the texture of the brush, making it less effective,” she says.
However, too much fluoride can cause children’s enamel to become porous, leading to teeth becoming mottled. This is called dental fluorosis, and in severe cases teeth can decay or crack. To avoid this, use children’s toothpaste.